StackExchange and CrossValidated: An Epidemiologist’s Review


This seems like as good a day as any to review CrossValidated, and the whole StackExchange constellation of websites. It’s been a month since I joined, exactly, and today I also crossed the 1,000 reputation threshold on the site. So why not give my impressions of it?

First, how I got there in the first place. I’ve been essentially learning Python and C as I go, working on my dissertation research. This, predictably, has resulted in some problems – and I happened across StackOverflow as a decidedly decent place to get answers to what were admittedly pretty rookie questions in a hurry – and at all random hours of the night. From there, I drifted over to their statistics site, CrossValidated, where I hoped I might do a little more good than just the asking of random programming questions.

More after the jump…

Some thoughts, both good and bad, about CrossValidated, and the community driven question-and-answer concept:

The Good:

First, like it says on the tin – have a question, ask it, get an answer. One the community, hopefully a knowledgable community, can help screen the good answers from the bad. And for most statistics questions, it does a decent job of it. Some more obscure ones don’t get answered, and the farther afield you get from straight-up statistics and into applied work, the more likely it is to go unanswered. Part of the reason I may have accumulated the reputation I have on the site in a month or so of time is that there were a lot of…low hanging fruit Epidemiology questions that had gone unanswered. But answers when they come are clear, well-sourced, and in my experience pretty damned good.

The sites in general are great for the kind of nagging questions about computing that come up and don’t get covered in classes and the like. Lingering questions about programming, hardware, interacting with big, scary cluster computers using command line interfaces…StackExchange is a decent place to get those kinds of questions sorted.


Some of them are a little off-kilter for the specific state-of-the-art in Epidemiology, but this is a pretty common phenomena. Each field has its own conventions, its own rules and its own way of doing things. Cross-field advice is often a little off. This, in my experience, is especially true when talking to dedicated statisticians – their answers are very, very good, but they require a little bit of processing to get to a usable form.

Software questions are common on the site, and tend to get answered with answers in R. Which is great…if you’re intending to use R. If you’re not – say, again, you’re in a more applied field where there’s a different standard, like SPSS or SAS, you’ll probably get decent theoretical answers, but software specific questions on platforms outside R may struggle to find answers.

CrossValidated is also undeniably a somewhat more obscure site than the bigger components of the StackExchange system – which means the answers are more easily dominated by a single user or small group of them. That does suggest some vulnerability to pushing a particular agenda or two – what if all the contributing users are dirty, filthy frequentists or some such!? I haven’t seen evidence of this problem particularly, but there is a decidedly small population on the site relative to some others.

The Bad:

Some of the questions – to be blunt – will put in you a profound fear of the state of research. But contributing to the site hopefully helps with that in its own, small way.

Stop by, check it out, consider posting on CrossValidated – or any of the other number of StackExchange sites. Programming, server administration, photography, bicycles…there’s options for whole slew of possible interests – and a site to suggest and build support for others, though that process is admittedly a long and hard one.

7 Responses to “StackExchange and CrossValidated: An Epidemiologist’s Review”

  1. 1 MW

    Good review and I agree on all parts. I recently started contributing to CrossValidated and have found that though it’s not nearly as lively as StackOverflow or the MathSE, I’ve already found some interesting discussions and am glad the site exists. If not for this dissertation, I’d spend more time perusing the backlog of unanswered questions and replying to some :-P.

    Nice blog, btw

  2. 2 Faheem Mitha

    Not sure what you mean by “Some of the questions – to be blunt – will put in you a profound fear of the state of research.” Care to clarify?

    Regards, Faheem

    • Faheem – essentially, you occasionally get questions where the answer is “Step away from the keyboard, find someone who knows what they’re doing” or “How did your dissertation committee let you get this far without figuring out what you were doing?”

      • 4 Faheem Mitha

        Ok, but I’m not sure what your point is. You mean they are not helpful replies?

      • No – mostly a small number of questions make me, a data scientist, cringe in horror. Going to try an analogy. You post on a car repair how-to forum. On occasion, you get questions that have a picture of a very expensive sports car, wrapped around a telephone pole, with the engine laying half-a-block away. The question? “This just happened, what size wrench should I use to fix?”

        Some very well intentioned experts will then try to help, but in the back of my mind is always “How did you get to this point in the first place?”

      • 6 Faheem Mitha

        I see. Thanks for the clarification.

  1. 1 The Art of Organizing CHAOS - Blog – Stack Exchange

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